In recent years, as the semiconductor industries and the ceramic industries has been advancing, demand for silicon compound as a main raw material in the industries has become great. The silicon compound, for example, such as silane [SiH.sub.4 ], tetraalkoxysilane [Si(OR).sub.4 ], of which substituents are the same has been used broadly. Additionally, increase of demand for a compound such as trialkoxyfluorosilane also has become large.
By the way, for manufacture of trialkoxhalosilane [XSi(OR).sub.3 ] (where, X is chlorine, bromine or iodine) other than trialkoxyfluorosilane, a reaction of Si(OR).sub.4 and HX (where, X is chlorine, bromine or iodine) has been considered. In this reaction, however, a plurality of products such as X.sub.3 Si(OR), X.sub.2 Si(OR).sub.2, XSi(OR).sub.3 and Si(OR).sub.4 are produced. Moreover, the boiling points of these products are close each other, so that it was impossible to obtain a high purity product. By these reasons, adoption of the reaction of Si(OR).sub.4 and HF has never been considered to manufacture FSi(OR).sub.3, because it is considered that this case also has the same troublesome problems as above.
That is, it is only proposed for the methods of manufacturing FSi(OR).sub.3 using antimony compound or aluminum compound (J. Am. Chem. Soc., 68, 76(1946), Nature, 158,672(1946), U.S. Pat. No. 3,374,247), for example: ##STR1## using complicated organic silicone compounds as starting materials, for example, EQU Si(OC.sub.2 H.sub.5).sub.4 +(C.sub.6 H.sub.5)CH.sub.3 SiF.sub.2 .fwdarw.FSi(OC.sub.2 H.sub.5).sub.3 +F.sub.2 Si(OC.sub.2 H.sub.5).sub.2 +(C.sub.6 H.sub.5)CH.sub.3 Si(OC.sub.2 H.sub.5)F+Si(OC.sub.2 H.sub.5).sub.4.
When using the above manufacture methods, however, it may occur that antimony or aluminum as a raw material mixes into the product as a metal impurity. Also, an antimony compound is a poisonoum substance, so that it is troublesome to handle it. Additionally, if this method is adopted for a production method in a factory, environmental conservation must be considered. Moreover, the complicated organic silicone compound such as (C.sub.6 H.sub.5)CH.sub.3 SiF.sub.2 or (C.sub.6 H.sub.5)CH.sub.3 Si(OC.sub.2 H.sub.5)F is expensive and difficult to obtain it, so that this method is not suitable for a factory production method.